{65 -4-N-butoxyphenyl-{60 ,{62 -dibromo-{66 {300 ,{330 -crotonic acid lactone

ABSTRACT

A compound of the formula WHEREIN R1 is hydrogen, or alkoxy having from 1 to 6 carbon atoms, R2 is hydrogen, or hydroxy or alkoxy having from 1 to 6 carbon atoms, and R3 is alkoxy having from 1 to 6 carbon atoms, with the proviso that when R1 and R2 are both hydrogen, R3 is alkoxy having from 2 to 6 carbon atoms, and wherein A is   X in these last two residues being chlorine or bromine. An example of a lactone is gamma -4-n-butoxyphenyl- Alpha , Beta dibromo- Delta , -crotonic acid lactone. An example of the hydrolysis product is Beta -4-n-pentyloxybenzoyl- Beta bromoacrylic acid. The compounds have a broad spectrum cytostatic activity and a low acute chronic toxicity.   OR IS

Unite States Patent [191 Semonsky et al.

[ 1 Mar. 25, W75

[ y-4-N-BUTOXYPHENYL-a,[3-

DlBROMOA--CROTONIC ACID LACTONE [75] Inventors: Miroslav Semonsky; Viktor Zikan;

Vaclav Jelinek,all of Prague, Czechoslovakia [73] Assignee: Spofa United Pharmaceutical Works, Prague, Czechoslovakia 22 Filed: Oct. 15, 1971 i 1 Appl. No: 189,764

Related U.S. Application Data [63] Continuation of Ser. No. 705.927. Feb. 16. 1968,

OTHER PUBLICATIONS Chem. Abstracts, Vol. 57. 1962, (14986 e to i and 14987 a-d relied on).

Primary IimmincrDonald G. Daus Asxixmnt Iirumincr-Anne Marie T. Tighe Attorney. Agent, or FirmMichael S. Striker [571 ABSTRACT A compound of the formula R2 A I wherein R is hydrogen, or alkoxy having from 1 to 6 carbon atoms, R is hydrogen, or hydroxy or alkoxy having from 1 to 6 carbon atoms. and R is alkoxy having from 1 to 6 carbon atoms, with the proviso that when R and R are both hydrogen, R is alkoxy having from 2 to 6 carbon atoms, and wherein A is or is l 1 -c0-c=cacoon X in these last two residues being chlorine or bromine. An example of a lactone is y 4-n-butoxyphenyl-a.fidibromo-A crotonic acid lactone. An example of the hydrolysis product is B-4-n-pentyloxybenzoyl-flbromoacrylic acid. The compounds have a broad spectrum cytostatic activity and a low acute chronic toxicity.

1 Claim, N0 Drawings y-4-N-BUTOXYPHENYL-a,B-DIBROMOA CROTONIC ACID LACTONE This is a continuation of application Ser. No. 705,927 filed Feb. 16, 1968, now abandoned.

BACKGROUND OF THE INVENTION a-4-methoxyphenyl-afi-dichloro-A B -crotonic acid lactone has already been described p'reviously,'and the same applies to the corresponding dib'romocompound; U.S. Pat. No. 3,105,850. Likewise, B-4- methoxybenzoyl-B-bromoacrylic acid and the corresponding chloroacrylic acid have become known in connection with a study of the possible cytostatic com pounds. However, the one compound, ,8-4- methoxybenzoyl-B-bromoacrylic acid, which has been used in medical practice on a limited scale, can only be administered parenterally in the form of its sodium salt.

Besides, it appeared desirable to improve the toxicityrating and the process of making the compounds of this general group.

In addition, better and more significant results regarding the cytostatic action in connection with a broad variety of tumors appeared highly desirable.

The previously known methoxybenzoyl compounds also presented problems of synthetic formation. To obtain the lactone from the hydrolyzed acid, anisole was reacted with B-formyl-a,B-dichloroacrylic acid (mucoehloric acid) in the presence of a reagent such as poly-. phosphoric acid. This process required a comparatively large amount of this acid, which is not easily made, and.

therefore resulted in a rather large volume of reaction mixture and a relatively poor yield and limited reproducibility. There was also the risk of decomposition both of the starting compound and the reaction prod-- uct. In addition. certain derivatives could not be formed at all with polyphosphoric acid as, for instance, the y-4-hydroxy-2-methoxyphenyI-a,B dibromocrotonic acid lactone.

Other problems existed in the hydrolysis of the lactone back to the acid, for which previously magnesium oxide or calcium carbonate had been suggested together with a water-miscible solvent such as dioxane. (See U.S. Pat. No. 3,l05,850) The use of these salts, such as the magnesium salt, affects the stability of the materials during the course of the reaction and thus affects also the yield and the purity ofthc compounds ob tained.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide novel cytostatic compounds which have an in creased and broad species cytostatic action.

It is a further object of the invention to provide such compounds which can be administered orally and have a low acute and chronic toxicity.

It is a still further object of the invention to provide improved processes for condensing the mucohalogenoacid to the lactone and converting. the latter by further processing to a aroyl-substituted halogenoacrylic acid. It is in particular an object of the invention in this connection to provide processes in both instances which avoid decomposition of the starting products or the final reaction products and result in improved yields and purity and have a high'reproducibility.

These objects are met by a compound of the formula wherein R is hydrogen, or alkoxy having from 1 to 6 carbon atoms, R is hydrogen, or hydroxy or alkoxy having from 1 to 6 carbon atoms, and R is alkoxy hav ing from 1 to 6 carbon atoms, with the proviso that when R and R are both hydrogen, R is alkoxy having from 2 to 6 carbon atoms, and wherein A is or is l -COC-CIICOOII X in these last two residues being chlorine or bromine.

An example of a lactone is y-4-n-butoxyphenyl-a,B- dibromo-A crotonic acid lactone. An example of the hydrolysis product is fi-4-n-pentyloxybenzoyl-fibrcmoacrylic acid.

The lactone-type compound is formed by condensing a mucohalo acid of the formula DESCRIPTION OF THE PREFERRED EMBODIMENTS I. THE LACTONES The crotonic acid lactones of the invention have been submitted to broad selection tests regarding their antineoplastic action on different transplantable tumors in the case of oral administration. More detailed tests were then carried out, as follows, with y-4-nbutoxyph enyl-afi-dibromo-A l3 -crotonic acid lactone. These tests showed the following results: ACUTE TOXICITY It was determined that the LD 50 in mice was 16 g/kg of body weight in the case-of oral administration. This compared with 320 mg/kg in the case of the 5-4- methoxy-benzoyl-B-bromoacrylic acid of the prior art (U.S. Pat. No. 3,105,850). CHRONIC TOXICITY The chronic toxicity was determined by tests with groups of 10 males and 10 females each on rats of the Wistar species over a period of 3 months. During this period, the animals were given doses of 50, I00 and ZOOmg/kg in the different groups, per day, and by oral administration in the form of suspensions in water. From the histological, biochemical and hematological investigation or determination it was found that the The higher dosis (100 and 200 mg/kg daily per os) resulted in a moderate microscopically detectable liver and spleen injury when administered under the same conditions, and in the case of females caused a slight effect on the blood proteins in the direction of hyperproteinemia.

High cytostatic action of the butoxyphenylsubstituted crotone lactone defined above was found to exist in the case of certain transplantable tumors, not only in the form of an inhibition of the tumor growth, but primarily in the form of a significant prolongation of the survival time of the treated animals. To specifically determine these actions, the following seven types of transplantable tumors'were implanted in the animals and subjected to the investigation:

S Hi (rocker-sarcoma HK adenocarcinoma of the mammary gland A'l li Ehrlich-ascitescarcinoma Kr 2 cancerous-ascitcs-sareoma Y Yoshida-ascilessarcoma in rats The administration to the animals was effected, in the case of firm (solid) tumors (S 180 and HK), beginning with the third day after the transplantation and for a period of 12 days, once daily. In the case of ascites tumors (ATE, S 37, Kr 2, 6C;,HED, and Y), the administration was effected once daily for days, starting with the second day after the transplantation. After completion of the administration, the weight of the prepared tumors was ascertained in a first .test group of 10 animals; In another test group of 10 animals, the'survival time of the animals was noted.

In the second test groups involving ascites tumors 6C;,HED and Y, only the survival time in a IO-animal group was noted. The average size of the tumors and the average survival time were then compared with the average values obtained in a parallel groupof untreated animals. The differences were satistically calculated by the t-Test and evaluated. The results are indicated in the following Table:

The activity of the compound under investigation was expressed by a fraction in which the numerator gives in percentage the average size of the tumor in a test group compared with the average size of the tumor in an untreated control group, which latter was taken as 100%. The denominator shows, in percentage, the average survival time of the treated animals compared with the average survival time of an untreated control group, which was taken as 100%. The test results show a substantially therapeutic cancerostatic action of the investigated compound in the case of sarcoma S 180,

adenocarcinoma of the mammary gland HK, of the Ehrlichascitescarcinoma ATE and the Yoshidaascitessarcoma Y.

The lactones of the present invention are preferably made by condensinga mucohalo acid of the formula cad-c c-cooa l t 11 x x wherein X is bromine or chlorine. with a substitutedbenzene of;the formula wherein R,, R and R have the same meaning as given above in the case of Formula I. This condensation is preferably carried out in the presence of anhydrous zinc chloride or a mixture of anhydrous zinc chloride with phosphorus pentoxide at a temperature between and 85C and preferably between and C. The substantially anhydrous zinc chloride should contain at most 5% water and is used in an amount by weight half of that or equal to that of the mucohalogenic acid of Formula II. If desired, the zinc chloride may be mixed with 5 to 20% phosphorus pentoxide. The use of these agents in the indicated condensation reaction is substantially superior to the prior art reactions which were carried out with polyphosphoric acid. The comparatively cumbersome requirement to have available a large amount of the polyphosphorus acid is avoided. The volume of the reaction mixture thus becomes smaller and the yield increases and the reaction is more easily reproducible. The starting products and the reaction product are subject to a smaller risk of decomposition. In addition, it is possible to form certain derivatives, for instance, y-4-hydroxy-2 -methoxyphenyl-a,B-dibromocrotonic acid lactone, which could not be made when using polyphosphoric acid as the condensation agent.

The optimum time of reaction depends on the character of the substituted benzene of Formula llI. It can vary between 15 minutes and 8 hours, the prolongation of the reaction does not ordinarily have a perceptible Dosage mg/kg per diem Total 5 I80 HK ATE S 37 Kr2 (iC HED Y 201] I000 69/l l7 8 H88 l09/l00 300 i500 54/l l7 effect on the yield in view of the non-deleterious nature of the condensation agent.

The isolation of the lactones from the reaction mixture is very simple. It can, for instance, be effected by the distribution of the product between chloroform and water, evaporation of the organic portion up to dryness, and purification of the residue by recrystallization EXAMPLE I y-4-n-hexyloxyphenyl-afi-dibromo-A B -crotonic acid lactone A mixture of 25.8 g of mucobromic acid, 13.6 g anhydrous zinc chloride, 1.36 g phosphorus pentoxide and 17.8 g n-hexylphenylether is heated upon exclusion of the humidity of the air and upon stirring for 5 hours in a bath maintained at 7580C. After cooling down of the molten mixture to about 40C, 125 ml of chloroform and 50 ml of water having a temperature of about 30C are added, and the resulting mixture is subjected to thorough stirring. The chloroform layer is separated and subjected to repeated shaking with water and drying over anhydrous sodium sulfate. The solvent is removed by distillation after filtration. There are obtained 36.1 g (86%) of a viscous crude product which furnishes the recrystallization material (methanol) after chromatography over a silica gel column (using benzene as elucnt) in a yield of 34.4 g (82%) and has a melting-point of 56-58C.

EXAMPLE ll y-4-hydroxy-2-methoxyphenyl-afi'dibromo-A B crotonic acid lactone A mixture of 25.8 g mucobromic acid, 12.4 g resorcinolmonomethylether and 13.6 g anhdrous zinc chloride are heated upon exclusion of air humidity and stir ring for 3 hours in a bath that is maintained at 75-80C. After treating the reaction mixture as in the preceding Example but without chromatography, a crude product is obtained in a yield of 28.7 g )79/(). After recrystallization from methanol, the pure material is found to have a melting-point of between 155l56C.

EXAMPLE Ill y-4-n-pentyloxyphenyl-a,B-dichloro-A -crotonic acid lactone 1 By using 16.9 g mucohloric acid, 16.4 g n-pentylphcnylether, 13.6 g anhydrous zinc chloride and 1.36 g phosphorus pentoxide in a procedure as indicated in the preceding Examples. there is obtained the product as stated in the heading of this Example, at a yield of 28.6 g (91% lts melting-point after recrystallization from methanol is 58-59C.

EXAMPLES IV X In the same manner, using exactly the same mol relationship of the several reaction components and the same amounts of anhydrous zinc chloride and phosphorus pentoxide, yields from 80-95% of the following compositions were obtained:

4. y-4-ethoxyphenyl-a,B-dibromo-A -crotonic acid lactone, m-p 96-97C (methanol) 5. y-4-propyloxyphenyl-o B dibromo-A crotonic acid lactone, m-p 57-58C (methanol) 6. y-4-n-butoxyphenyl-afi-dibromo-A crotonic acid lactone, m-p 7475C (methanol) 7. y-4-n-pentyloxyphenyl-a,B-dibromo-A crotonic acid lactone, m-p 82-84C (methanol) 8. y-Z,4-dimethoxyphenyl-a,B-dibromo-A B crotonic acid lactone, m-p 1l2-l 14C (methanol) 9. y-2,3,4-trimethoxyphenyl-a,B-dibromo-A crotonic acid lactone, m-p ll7l 19C (methanol) 10. 'y-2,4,6etrimethoxyphenyl-a,,B-dibromo-A B crotonic acid lactone, m'-p 176178C (methanol) 11. THE HYDROLYSIS PRODUCTS The lactones previously described can easily be hydrolyzed to form halogenoacrylic acids of the following formula:

wherein X is chlorine or bromine, R is hydrogen or alkoxy having 1 to 6 carbon atoms, R is hydrogen or hydroxy or alkoxy having 1 to 6 carbon atoms, and R is alkoxy having 1 to 6 carbon atoms, with the proviso that when R, and R are both hydrogen, R shall be alkoxy having 2 to 6 carbon atoms.

The halogenoacrylic acids defined have been found to possess a therapeutic action on animals with transplantable tumors in the case of parenteral administrze tion. This action was without undesired side effects.

It was furthermore found that, for instance, the 8-4- n-pentyloxybenZoyl-B-bromoacrylic acid was effective therapeutically also after peroral administration. This is a great advantage over the previously knwon 8-4- methoxybenzoyl-B-bromaocrylic acid, which could be used only parenterally in the form of its sodium salts.

The halogenoacrylie acids can be obtained by hydrolysis of the previously described crotonic acid lactones of the formula:

wherein X, R,, R and R have the same meaning as in Formula IV, with a mixture of water and a watermiscible solvent, preferably dioxane, in the presence of zinc oxide and at the boiling temperature of the reaction mixture.

The amount of Zinc oxide used for the hydrolysis is preferably from 1 to 4 mols relative to 1 mol of the lactone used as starting product.

Under the stated conditions, the hydrolysis proceeds with very good yields, in some cases almost quantitatively. The zinc salt of the B-aroyl-B-halogenoacrylic acid is substantially more stable compared, for instance, with the magnesium or sodium salt, and is not subject to decomposition during the reaction. The hydrogen halide that is formed during the hydrolysis of the lactone is bound in the form of the corresponding zinc halide. The use of zinc oxide thus permits the production of the desired acids with a high yield, usually above and at an almost analytical degree of purity, particularly because of the high stability of the zinc salt formed and the small possibility of deleterious action on the salt.

The B-aroyl-halogenoacrylic acids of the Formula lV, can, for instance, be isolated by subjecting the reaction mixture after completion of the hydrolysis to evaporation to dryness under reduced pressure, dissolving the residue in water upon addition of sodium bicarbonates, whereupon the desired acid is liberated from the solution of its sodium salt by acidifying it with hydrogen chloride. It is also possible to proceed in the manner that the residue is distributed between dilute hydrochloric acid and chloroform, whereupon the chloroform extract is evaporated to dryness and the residue is purified by crystallization.

EXAMPLE Xl A solution of 22.2 g ,B-4-ethoxybenzoyl-0z,B-dibromo- A B -crotonic acid lactone in 20' ml dioxane is added dropwise to a boiling mixture of 240 ml water and dioxane (in the ratio 1:1) and 5 g zinc oxide. The addition is effected within minutes and at a speed sufficient to keep the reaction mixture continuously at the boiling-point. After permitting the mixture to boil for another 75 minutes, the solvent is removed from the mixture by distillation at 40C and 14 Torr and the residue is extracted for one hour with a warm solution (35C) of 24 g sodium bicarbonate in 240 ml water. The solution obtained of the [3-4-ethoxybenzoyl-B- bromoacrylic acid sodium salt is acidified after filtration with cone. sulfuric acid and upon vigorous stirring to obtain a pH between 2 and 3. The acid that separates out is removed by suction after cooling to 5C and is dried in air at room temperature. The yield after recrystallization from benzene is 17.2 g (94%), melting-point between l49-l50C.

The reaction mixture is preferably treated after removal of the volatile portions by distillation in amanner whereby the residue is shaken with hydrochloric- EXAMPLES XII XX In the same manner as in.the preceding Example, using the same mo] ratios of reaction products and the same general reaction medium, the following compositions were obtained in a yield between -90%:

l2. ,B-4-n-propoxybenzoyl-B-bromoacrylic acid, m-p

ll8l 19C (benzene) 13. [3-4-n-butoxybenzoyl-B-bromoacrylic acid, m-p

l22123C (benzene-hexane) l4. B-4-n-pentyloxybenzoyl-B-bromoacrylic m-p 103104C (benzene-heptane) l5. B-4-n-hexyloxybenzoyl-B-bromoacrylic acid, m-p

9899C (benzene hexane) 16. l3-4-n-pentyloxybenzoyl-B-bromoacrylic m-p 94-95C (benzene) l7. B-2,4-dimethoxybenzoyl-B-bromoacrylic acid,

m-p l33135C (benzene) 18. B-2,3,4-trimethoxybenzoyl-B-bromoacrylic acid,

m-p l20-121C (benzene) l9. B-2,4,6-trimethoxybenzoyl-B-bromoacrylic acid,

m-p 156l57C (benzene) 20. [3-2,3,4-trimethoxybenzoyl-B- chloroacrylic acid,

m-p l14l15C (methanol) What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. y-4-n-butoxyphenyl-a, B-dibromo-A B crotonic acid lactone.

acid,

acid, 

1. Y-4-N-BUTOXYPHENYL-A, B-A DIBROMO-$ -CROTONIC ACID LACTONE. 